Turtle库
2016-01-13 17:08
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下列turtle库的简单常用指令
forward(distance) #将箭头移到某一指定坐标
left(angel) right(angel)
penup() #提起笔,用于另起一个地方绘制时用,与pendown()配对使用
goto(x,y)
home()
circle(radius)
speed()
树的绘制
观察:对称树, 从主杆出发以一定角度向左向右生成对称的枝丫, 且每一棵枝杈上以相同的角度生成更小的左右枝杈,如此往复。
联系:所学内容,易想到利用递归程序实现;
森林的绘制
如何画出多棵树,甚至整片森林呢?
答案很简单,只要在画每棵树之前调整画笔的位置,调用画树程序,就可以从新位置生成一颗新树了。
利用模块化的函数思想,调整代码:
将每棵树的绘制以maketree函数封装,参数x,y为画树的起点位置即树根位置。在main函数中只要以
不同的参数设置来调用maketree函数就可以完成多棵树的绘制了
图像:
forward(distance) #将箭头移到某一指定坐标
left(angel) right(angel)
penup() #提起笔,用于另起一个地方绘制时用,与pendown()配对使用
goto(x,y)
home()
circle(radius)
speed()
#五角星图形 from turtle import Turtle p = Turtle() p.speed(3) p.pensize(5) p.color("black", 'yellow') #p.fillcolor("red") p.begin_fill() for i in range(5): p.forward(200) #将箭头移到某一指定坐标 p.right(144) #当前方向上向右转动角度 p.end_fill()
树的绘制
观察:对称树, 从主杆出发以一定角度向左向右生成对称的枝丫, 且每一棵枝杈上以相同的角度生成更小的左右枝杈,如此往复。
联系:所学内容,易想到利用递归程序实现;
# drawtree.py from turtle import Turtle, mainloop def tree(plist, l, a, f): """ plist is list of pens l is length of branch a is half of the angle between 2 branches f is factor by which branch is shortened from level to level.""" if l > 5: # lst = [] for p in plist: p.forward(l)#沿着当前的方向画画Move the turtle forward by the specified distance, in the direction the turtle is headed. q = p.clone()#Create and return a clone of the turtle with same position, heading and turtle properties. p.left(a) #Turn turtle left by angle units q.right(a)#Turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions. lst.append(p)#将元素增加到列表的最后 lst.append(q) tree(lst, l*f, a, f) def main(): p = Turtle() p.color("green") p.pensize(5) #p.setundobuffer(None) p.hideturtle() #Make the turtle invisible. It’s a good idea to do this while you’re in the middle of doing some complex drawing, #because hiding the turtle speeds up the drawing observably. p.getscreen().tracer(10,0) #Return the TurtleScreen object the turtle is drawing on. #TurtleScreen methods can then be called for that object. #p.speed(10) p.left(90) #Turn turtle left by angle units. direction 调整画笔 p.penup() #Pull the pen up – no drawing when moving. p.goto(0,-200)#Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation. p.pendown()# Pull the pen down – drawing when moving. 这三条语句是一个组合相当于先把笔收起来再移动到指定位置,再把笔放下开始画 #否则turtle一移动就会自动的把线画出来 #t = tree([p], 200, 65, 0.6375) t = tree([p], 200, 65, 0.6375) main()
森林的绘制
如何画出多棵树,甚至整片森林呢?
答案很简单,只要在画每棵树之前调整画笔的位置,调用画树程序,就可以从新位置生成一颗新树了。
利用模块化的函数思想,调整代码:
将每棵树的绘制以maketree函数封装,参数x,y为画树的起点位置即树根位置。在main函数中只要以
不同的参数设置来调用maketree函数就可以完成多棵树的绘制了
# drawtree.py from turtle import Turtle, mainloop def tree(plist, l, a, f): """ plist is list of pens l is length of branch a is half of the angle between 2 branches f is factor by which branch is shortened from level to level.""" if l > 5: # lst = [] for p in plist: p.forward(l)#沿着当前的方向画画Move the turtle forward by the specified distance, in the direction the turtle is headed. q = p.clone()#Create and return a clone of the turtle with same position, heading and turtle properties. p.left(a) #Turn turtle left by angle units q.right(a)#Turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions. lst.append(p)#将元素增加到列表的最后 lst.append(q) tree(lst, l*f, a, f) def maketree(x, y): p = Turtle() p.color("green") p.pensize(5) p.hideturtle() p.getscreen().tracer(30, 0) p.left(90) p.penup() p.goto(x, y) p.pendown() t = tree([p], 110, 65, 0.6375) print(len(p.getscreen().turtles())) #用了多少个turtle绘制 def main(): maketree(-200, -200) maketree(0, 0) maketree(200, -200) main()
图像:
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